1. Field of Invention
Embodiments of the present invention relate generally to semiconductor devices and methods of manufacturing semiconductor devices, and more particularly, to a non-volatile memory device and a method of manufacturing the non-volatile memory device.
2. Description of the Related Art
Generally, non-volatile memory devices keep data when power is turned off and can be selectively programmed as required by the user. Memory devices such as one-time programmable (OTP) memory devices or multi-time programmable (MTP) memory devices can be used for one-time or multiple-time programming. Thus, demand for such memories is gradually increasing.
The values of non-volatile memory devices are not the characteristic feature of the non-volatile memory devices, but the assisting function to various semiconductor products. For example, OTP and MTP memory devices can be embedded in an integrated circuit (e.g., a display driver IC (DDI), an LCD driver (LDI), etc.) and be used to record information. Thus, OTP and MTP memory devices have a small memory capacity.
Cells of a conventional memory device have a stack-type structure in which a tunneling oxide film, a floating gate, a dielectric film, and a control gate are sequentially formed on a semiconductor substrate, and in which a source and drain are formed in the semiconductor substrate on both sides of the control gate. A memory device having such a stack-type structure operates by changing a threshold voltage of the cells while electrons are moving towards the tunneling oxide due to a strong electric field. However, since the cells of the memory device have a stack-type structure, additional processes are required to embed the stack in an integrated circuit. Thus, the number of manufacturing process required to form the integrated circuit is increased and the process of forming memory device becomes complicated, thereby increasing manufacturing costs.
Conventional memory devices typically require a capacitor. Conventionally, capacitors are formed by sequentially forming a dielectric film and a doped polysilicon film serving as an upper electrode on a doped polysilicon film serving as a lower electrode. If these processes for forming the capacitor are added, the manufacturing cost of non-volatile memory devices that require a small memory capacity as described above can be increased further. As a result, manufacturing costs can be undesirably increased while greatly reducing productivity.